Process of recovering nicotine from tobacco



Sept. 19, 1933; H. K. MOCONNELL 1,927,180

PROCESS OF REcovERiNe NICOTINE FROM TOBACCO I Filed June 28, 1924 Patented Sept. 19, 1933 P-ATENT OFFICE PROCESS OF RECOVERING NICOTINE FROM TOBACCO Henry K. McConnell, Richmond, Va., assignor to Tobacco By-Products tion, Louisville, Ky., ware and Chemical Corpora- -a corporation of Dela- Application June 28, 1924. Serial No. 722,912 I 6 Claims.

This invention relates to a process for the recovery of nicotine from tobacco material.

The object of the invention-is to provide a process which gives a high efliciency in the recovery of the nicotine at a relatively low cost as compared with processes and apparatus heretofore employed.

The invention will be explained in connection with the accompanying drawing and then more 10 particularly pointed out.

The drawing is a diagrammatic view partly in section of a complete plant, for the recovery of nicotine from tobacco material in accordance with my invention, the nicotine being recovered in the form of a nicotine salt.

Referring to the drawing, A is an extracting drum and E a dryer drum of the type described in detail in my application Serial No. 619,641, filed February 17, 1923, (now Patent No. 1,551,-

676) these drums being connected by a conduit device H. The extracting drum A has a suitable device for supplying tobacco material, as indicated at 10 and a suitable outer stationary head as indicated at G, through which the dried material, deprived of its nicotine, is discharged.

All of this mechanism constitutes an apparatus for driving 01f nicotine-containing vapors from tobacco material, and is used here merely as one example of such apparatus, it being understood that other apparatus may be employed for driving off such vapors. The details of construction and operation of such apparatus are fully described in my application above identified and therefore need not be specifically described here. At 13 is shown thevapor outlet pipe from said apparatus,'this being shown as connected to the suction inlet of a fan C, all as shown and described in said application.

In the present invention the vapor outlet of 40 an apparatus for evolving nicotine-containing vapors from tobacco material is connected to a tower apparatus so proportioned'and constructed as to permit the vapors to travel at a relatively rapid rate through such tower apparatus while at the same time insuring contact between the nicotine in vapor form and a suitable reagent, such as an acid solution, for such a duration of time that all the nicotine will be removed from the vapors, whereupon the latter may then be discharged from the tower apparatus. In the best embodiment of the invention the reagent.

employed to combine with the nicotine is one giving an exothermic reaction with the nicotine, as for example, a solution of sulfuric acid, so that the heat evolved will tend to prevent the cooling of the vapors in the tower apparatus, thereby allowing said vapors to be utilized, after they leave the tower apparatus, for heating purposes, as for example, to heat the dryer or to heat suitable vacuum pans in which a solution of nicotine compound may be concentrated.

In the'particular tower apparatus illustrated two towers are employed, through which the nicotine-containing vapors are passed in series. Each tower comprises a closed casing 35, 35 which may be of any desired shape in cross-section, usually circular, this casing being closed by a lid 36 at the top and having its lower end formed as a tray, as indicated at 37,.this tray extending outside the casing to form a liquid seal.

The casing has an inner lining of suitable material whichwill not be injured by the chemicals employed in acting upon the nicotine vapors. In the best embodiment of the invention the lining, indicated at 38, may be of suitable cement or suitable brickwork resting in the tray and provided with a series of openings at its bottom. The vertical flanges or walls of the tray 37 extend sufiiciently above the tops of the said openings to permit the maintenance of a liquid level in the tray above the tops of said openings, thereby forming a liquid seal.

The interior of the casing is supplied with a checker-work of suitable material, such, for example, as chemical-proof brick. This checkerwork is not carried entirely down into the lowest portion of the apparatus, but a space or chamber is left to serve as an inlet or distributing chamber. An opening is provided in the wall of this chamber to serve as an inlet for the ad- 'mission of vapors and gases, if any. These vapors, and any gases accompanying them, are

delivered to the vapor inlet of the tower 35 by a conduit 39 leading from the discharge outlet of the fan C. The second tower, 35*, when such is employed, has its vapor inlet supplied with vapors by a connecting conduit 40 leading from an upper chamber left at the top of the tower '35 above the checker-work. The upper chamber of the second tower 35 is connected to a discharge conduit 41 whereby any remaining vapors may be discharged from the apparatus. In the best embodiment of the invention this discharge conduit 41 is arranged to conduct the said vapors to apparatus capable of utilizing such vapors, as for example, to the jacket of an evaporating apparatus indicated on a smaller scale at N.

At a level lower than the trays, 3'7 of the tower apparatus arev arranged two acid tanks 42 and 43, respectively, the tray of the first tower having an overflow pipe as arranged to discharge into the tank while the tray of the second tank has an overflow pipe discharging into the tank 43. The two tanks are so connected that acid solution from the tank 43 may be transferred to tank a2 when desired. This connection is indicated at 4:6 and may be a pipe so located in. height that it will serve as an overflow from tank d3 to tank 42.

Suitable means is provided for transferring the acid solutions in the tanks 42 and 43 to the towers. In the apparatus illustrated the solution from tank is lifted to the top of the tower 35, by suitable elevating means, which in this case may be an acid=proof rotary pump, in

dicated at 427, connected by a pipe iii to a spraying device, a spray nozzle or rose is located within the chamber or the tower. The pipe 48 is provided with a faucet or cook 48 from which solution may be drawn when desired, as hereinafter explained. The liquid from the tank 43 may be elevated and sprayed into the upper chamber of the second tower by means, for example pump to and pipe 51 leading to a spray nozzle in the upper chamber of the second tower, not shown. The pumps 47 and are connected with their respective tanks by the suction pipes 52 and. 53

respectively, as will be clear from the drawing.

1* has been found that to provide a successful apparatus, there must be a certain relationship between the diameter of the checker-work and its height. The height should not be less than three times the diameter, and better results are obtained when the height is considerably more than three times the said diameter, for example 3.5 times. in a very satisfactory apparatus employed by me, the casings were 42 in diameter, the lining was of brick l" thick, the checkerwork was 34 diameter and. nine feet high, and by spacing the bricks of the checker-work the width.- of a brick apart, there was obtained 3.15 square feet of actual opening. With. this checker-work it was practical to work at a very high velocity of vapors through the checkerwork, viz: about 450 ft. per minute, while maintaining a much higher reaction efficiency than by methods and apparatus heretofore used in nicotine recovery.

In carrying out the process, which constitutes the invention, the tank s3 is provided with a a strong acid solution and the tank 42 with a dilute solution of acid. The acid employed is one which will combine with nicotine to form a salt and most advantageously, an acid which in so combining will evolve heat, thereby tending to maintain the temperature of the aqueous vapors accompanying the nicotine vapors There are several acids which will give the desired results, viz: sulphuric, hydrochloric, or acetic acids. In the further description of the process it will be as sumed that sulphuric acid is employed, as this will give the greatest evolution of heat.

The acid solution in the tank 42 is of about six tenths normal strength, while the acidsolution in the tank 43 is about double or triple normal strength, the term normal strength here used meaning 1 gm. equivalent in one liter ofsolution, that is to say, 49 grams of H2804 per liter of solution.

The capacities of the tanks and the power of the pumps is such that a sufiicient flow of the acid solutions may be maintained in the tower apparatus to insure the removal of all nicotine from the vapors accompanying it so that the latter will leave the tower apparatus entirely free from nicotine.

The tobacco material to be treated is run through the nicotine extracting apparatus as described in my application Ser. No. 619,641 (now Patent No. 1,551,616) and the vapors, which comprise steam and free nicotine in vapor form, are drawn from the extracting apparatus by the fan 6 and are blown into the chamber at the bottom of the tower 35. They rise in the tower and encounter the downward-dropping weak acid solution which forms a well sub-divided counter current. The acid reacts with a part or": the nico tine to form a nicotine salt which is dissolved by the water of the solution and this solution of Weak acid, containing some dissolved nicotine salt, flows downward into the liquid. seal at the bottom of the tower, from whence it overflows to the tank d2. Owing to the heat evolved by the reaction in. this tower, the aqueous vapors and any remaining free nicotine are not cooled to any appreciable extent, but pass in a hot condition to the bottom chamber of the next tower 35 through the connecting conduit 40. The Vapors rise through the checker-work of the said second tower and therein encounter the downward dropping strong acid solution. The acid reacts with any remaining free nicotine and the nicotine salt thereby formed is dissolved in the acid solution which flows downward to the liquid seal and then overflows into the tank 43. Further heat is evolved by the action of the acid solution on the nicotine, so that the aqueous vapor from the extracting apparatus is freed from its nicotine without being condensed to any appreciable extent, and in its hot condition passes from the last tower through the conduit ll. to the steam jacket of the apparatus to be heated, as for example the evaporating pan N where its heat is utilized, the steam being condensed, the water of condensation leaving the jacket through any suitable outlet, as for example the pipe n.

The acid solutions, after their first passage through the respective towers are returned again to said towers, carrying with them in solution the nicotine salt, so that, after such first passage, the solutions which flow downward in the towers are not merely acid solutions but acid and nicotine salt solutions. Whether or not the presence of the nicotine salt in the solution assists in the reaction between the acid and the vapors, I am unable to determine, but there is no disadvantage in this as the presence of the nicotine salt in the solution does not retard the reaction and the high eificiency obtained clearly justifies the process.

Samples of the solution in use in the first tower are takenat intervals from the faucet 48 and when the solution is nearly neutral, as determined by a test with litmus, a portion of the solution is drawn from the system through said cock 48 and concentrated in any suitable way as for example by evaporation in the vacuum pan N. The tank 42 is then supplied with acid, and nicotine salt solution from the tank 43, which can be done conveniently by stopping the pump 50, and allowing the solution from the tower 35 to fill up the tank 43 and overflow through the pipe, 46, into tank 42. Then the pump 50 is i started again and some 'fresh concentrated acid is added to the tank 43 to bring up the acid strength of the solution therein. In practice there may be enough condensation of the aqueous vapors from the extracting apparatus to supply the additional water required to replace that drawn off with the solution taken from tank 42. If not, some water may be added with the acid in tank 43.

What I claim is:

4 1. The process of recovering nicotine from tobacco material, which comprises driving ofi free nicotine in vapor form, together with aqueous vapors, from the tobacco material, then passing the mixed vapors in contact with a well subdivided current of an aqueous solution containing an acid capable of reacting exothermically with nicotine to form a salt, concentrating the solution containing the salt, and utilizing the heat of the nicotine-free aqueous vapors in the recovery of other nicotine.

2. The process of recovering nicotine from tobacco material, which comprises driving off free nicotine in vapor form, together with aqueous vapors, from the tobacco material, then passing the mixed vapors in contact with a continuously circulating countercurrent of a solution of an acid capable of reacting with the nicotine, and then in contact with a continuously circulating countercurrent of a solution of the same acid but of a higher acidity than the first solution, whereby the nicotine is removed from the vapors, withdrawing solution from the first countercurrent when it has become substantially neutral, replacing the withdrawn first solution with some of the second solution, replacing the withdrawn second solution with fresh acid, and concentrating the withdrawn first solution to obtain a strong solution of the nicotine salt.

3. The process of recovering nicotine from tobacco material, which comprises driving ofi free nicotine in vapor form, together with aqueous vapors from the tobacco material, then passing the mixed vapors in contact with a continuously circulating counter-current of a solution of an acid capable of reacting with the nicotine until said solution approaches neutrality, and then in contact with a continuously circulating countercurrent of a solution of the same acid but of a higheracidity than the first solution whereby the nicotine is removed from the vapors.

. 4. The process of recovering nicotine from tobacco material which consists in driving off therefrom nicotine in vapor form together with aqueous vapors, then passing these vapors while still in vapor form into contact with a flow of well-subdivided solution of an acid capable of.

reacting exothermically with nicotine to form a salt, maintaining the temperature of the aqueous vapors by the heat of the exothermic reaction, and passing the heated aqueous vapors away from the acid solution while still in hot vapor form.

5. In the process of forming a concentrated nicotine salt from a vapor mixture consisting of aqueous vapors and free nicotine, the steps which consist in repeatedly contacting with said vapor mixture a well-subdivided current of an aqueous solution of an acid capable of reacting exothermically with the nicotine to form a salt, until said current approaches neutrality, maintaining the temperature of the said vapor mixture by the heat of said reaction, withdrawing the vapor mixture from contact with said solution while still in vapor form and then repeatedly contacting with said withdrawn vapor mixture another well-subdivided current of the same acid as before, maintained at a higher acidity than the first, and withdrawing the remaining aqueous vapors from said second current while still in vapor form.

6. In the process of forming a concentrated nicotine salt from a vapor mixture consisting of aqueous vapors and free nicotine, the steps which consists in repeatedly contacting with said vapor mixture a well-subdivided current of an aqueous solution of an acid capable of reacting exothermically with the nicotine to form a salt, until said current approaches neutrality, maintaining the temperature of the said vapor mixture by the heat of said reaction, withdrawing the vapor mixture from contact with said solution while still in vapor form and then repeatedly contacting with said withdrawn vapor mixture another well-subdivided current of the same acid as before, maintained at a higher acidity than the first, and when the solution of the first current has approached neutrality withdrawing it, replac-' ing it by the second solution, and supplying a fresh acid'solution for the second current aforesaid.

HENRY K. McCONNELL. 

